Yep.. Seal off how they get in and then no problem..
I park my trailer on the side of my house. I have a 2 cord wood shed and forest all around... I place poison bait in the wood shed and when it's gone, I always find the dead mice/rats in the wood pile as I use it.
Wood shed in background.
I NEVER have had them in the 2 different trailers I've owned and parked within feet of that shed for the last 18 or so years I've had the 2 trailers, or in my house for that matter...
I don't even get them in my house's crawl space anymore... Sealed off one foundation vent I found and zip, zero nada.. But, in the wood shed... I buy bait by the bucket from amazon and it gets all eaten up.. And I find the bodies in the wood pile so I know it's the mice/rats eating it.
Anyway, gotta just close the doors to your rig and they can't get in in the first place... (yes, I know the door is open on my trailer in the pic!, ha, ha!)
Good luck!
Mitch
2013 F150 XLT 4x4 SuperCab Max Tow Egoboost 3.73 gears #7700 GVWR #1920 payload. 2019 Rockwood Mini Lite 2511S.